NAME

       lamssi - introduction to LAM System Services Interface (SSI)

DESCRIPTION

       The SSI in LAM/MPI is used to select one (or more) system services interfaces at run-time.

OVERVIEW

       LAM SSI instances are uniquely described in terms of "kinds" (also referred to as "types") and "modules".

       The  "kind"  refers  to  which  set  of system services the SSI instance will apply to.  For example, LAM
       currently has several kinds: "boot", "coll", "cr" and "rpi".  The  "module"  refers  to  a  specific  SSI
       instance of a given kind.  Each kind has o

       boot  modules  are  used  to  start  the  LAM  run-time  environment  (i.e.,  they  provide  the back-end
       functionality to lamboot(1)).  boot modules are discussed further in the lamssi_boot(7) man page.

       coll modules provide back-end algorithms and functionality for the MPI collective  communications.   coll
       modules are described in lamssi_coll(7).

       cr modules provide checkpoint/restart functionality for MPI jobs.  See lamssi_cr(7) for details.

       rpi  modules  provide  back-end  functionality  for  MPI  point-to-point communications.  rpi modules are
       detailed in lamssi_rpi(7).

VERBOSE OPERATION

       The user can force SSI modules to be verbose by  setting  the  LAM_SSI_ssi_verbose  environment  variable
       before invoking mpirun, or by using the -ssi command line switch to mpirun.  For example:

       mpirun -ssi ssi_verbose 1 C foo
           Tell the SSI modules to be verbose, and default to sending their output to stderr.

       The  ssi_verbose  kind is a "pseudo-kind" in that it is used to pass parameters to the main SSI meta-glue
       itself -- not to any particular kind.  It can take many different parameters to format where and how  the
       verbose output will be sent (note that at least one parameter must be specified, even if it is an invalid
       parameter).  Any combination of the following parameters may follow the ssi_verbose  kind  (separated  by
       commas):

       syslog
           Send the verbose output to the syslog.

       syslogpri:<priority>
           Set the syslog output priority to <priority>.  Using this paramter implies the syslog parameter.  The
           default priority is info (LOG_INFO).  Valid <priority> values are:  notice  (LOG_NOTICE),  info,  and
           debug (LOG_DEBUG).

       syslogid:<id>
           Use the ID <id> for the syslog prefix.

       stdout
           Send the verbose output to stdout.

       stderr
           Send the verbose output to stderr.

       file[:<filename>]
           Send  the  verbose output to a file in the LAM per-user, per-node meta information directory (usually
           located in /tmp).  If <filename> is specified, send the output to the file named lam-<filename>.   If
           <filename> is not specified, send the output to the file named lam-ssi.txt.

       fileappend
           Append  to  the file when sending the verbose output (create the file if it does not exist).  If this
           parameter is not given, if the file already exists, it will be  overwritten.   Using  this  parameter
           implies the file parameter.

       level:vlevel
           Indicate  the  specific  verbosity  level to be used.  Although the specific meaning of the verbosity
           level is left up to individual SSI modules, generally negative numbers mean no  verbose  messages,  0
           means  a  minimal  set of messages, and positive numbers mean more messages (the greater the positive
           number, the more output messages will be generated). If left unspecified any  any  other  ssi_verbose
           parameters are specified, the default level of 0 is used.

       If  multiple  parameters  are  passed  in  ssi_verbose, the output will be directed as implied by all the
       parameters.  If no valid parameters are passed (e.g., a single invalid parameter is passed), then  output
       will be directed to stderr by default.

       Also  note  that as with all SSI parameters, all of these values may be passed by setting the environment
       variable  LAM_SSI_ssi_verbose  before  invoking  mpirun.   However,  parameters  passed   through   "-ssi
       ssi_verbose" will take precedence over environment variables.

EXAMPLES

       mpirun -ssi ssi_verbose 1 C foo
           Since no valid parameters were passed, the verbose output will be sent to stderr.

       mpirun -ssi ssi_verbose file:output.txt,syslogpri:notice C foo
           Send  the verbose output to both the file lam-output.txt in the LAM user meta directory as well as to
           the syslog with a priority of LOG_NOTICE.

SEE ALSO

       lamssi_boot(7), lamssi_coll(7), lamssi_cr(7), lamssi_rpi(7), mpirun(1), lamboot(1), recon(1), lamwipe(1),
       LAM User's Guide